//Test1

List<String> list1 = new ArrayList<String>();

list1.add("Elem1");

list1.add("Elem2");

Map<List<String>, String> map = new HashMap<List<String>, String>();

map.put(list1, "Can get value.");

System.out.println("Elements of list1: "+list1);

List<String> list2 = new ArrayList<String>();

list2.add("Elem1");

list2.add("Elem2");

System.out.println("Elements of list2: "+list1);

System.out.println("Test1. Get value from HashMap(Key: list1) by the key list2: "+map.get(list2)+"\n");

//Test2

list1 = new ArrayList<String>();

list1.add("Elem1");

map = new HashMap<List<String>, String>();

map.put(list1, "Can get value.");//list1 only one element, and it's hash code is 67040897

list1.add("Elem2");//Add one element, even though ArrayList is a kinds of reference type, but map keys' hash code not change.

System.out.println("Elements of list1: "+list1);

list2 = new ArrayList<String>();

list2.add("Elem1");

list2.add("Elem2");

System.out.println("Elements of list2: "+list2);

System.out.println("Test2. Get value from HashMap(Key: list1) by the key list2: "+map.get(list2)+"\n");

//Test3

list1 = new ArrayList<String>();

list1.add("Elem1");

map = new HashMap<List<String>, String>();

map.put(list1, "Can get value.");

list1.add("Elem2");

System.out.println("Elements of list1: "+list1);

Map<List<String>, String> tempMap = new HashMap<List<String>, String>();

tempMap.putAll(map);//Will be recalculate the keys' hash code

list2 = new ArrayList<String>();

list2.add("Elem1");

list2.add("Elem2");

System.out.println("Elements of list2: "+list2);

System.out.println("Test3. Get value from HashMap(Key: list1) by the key list2: "+tempMap.get(list2));